POLYGON MACHINE
MONOBLOCK WELDED CEMENT SILO: MINERAL SILO
Monoblock welded silos are one-piece, cylindrical storage vessels for cement or mineral powders, fabricated from heavy-gauge steel plates by welding. Unlike bolted silos, they arrive as a single welded shell that requires minimal on-site assembly. This monoblock design yields a seamless, leakproof structure with essentially zero water permeability, ensuring contained, dust-tight storage. Typical capacities range from a few tens up to several hundred tons (e.g. 30–500 t), accommodating diverse batching-plant scales. Manufacturers like Polygonmachine build these silos with a strong emphasis on structural strength and longevity – for example using high-grade carbon steel and spiral or ring stiffening to resist internal pressure and wind loads. In a factory setting, the welded silo shell is lifted as a single unit and placed onto its foundation, greatly speeding installation.
Why choose Polygon Machine?
Polygon Machine delivers certified quality (TSE & ISO 9001), global expertise, and durable solutions from 30 m³/h to 240+ m³/h. Polygonmachine is a trusted partner in both compact and large-scale projects.
What cement silo types are available?
Stationary, mobile, and horizontal cement silos—plus cement feeders, filters, and safety systems. Every unit is customizable to match your storage, capacity, and operational requirements.
How is long-term support handled?
Polygon Machine ensures fast setup, training, and after-sales service, minimizing downtime. All plants include modern automation and safety features for easy, efficient use.
Overvıew / Design and Fabrication
Welded silos are usually cylindrical with a conical (or hopper) bottom and a domed roof. In one-piece monoblock construction, all panels and the roof are welded together in controlled factory conditions, often in a climate-controlled shop to ensure weld quality and coatings. The body typically uses steel plates (e.g. S355 structural grade) of 6–12 mm thickness (depending on diameter and height) and incorporates stiffening ribs or undercut spiral embossments to enhance rigidity. The silos rest on welded support legs or a skirt, with anchor-bolts cast in the concrete foundation. Polygonmachine’s designs include integrated access ladders and safety platforms around the silo body. A vented roof cap allows atmospheric pressure relief, and large manholes provide inspection access. All welded seams are inspected (often via NDT) before coating. Typical corrosion protection is a hot-dip galvanizing or multi-layer epoxy/paint system applied to the inside and outside of all steel surfaces. (Local reinforcements are added at welds and bolt areas, since these spots may have lower galvanizing thickness.) Together, these features yield a silo shell that is extremely robust and low-maintenance.
What are the main geometric components of welded silos?
Welded silos typically consist of a cylindrical body, a conical (hopper) bottom, and a domed roof.
How are monoblock (one-piece) silos manufactured?
In monoblock construction, all panels and the roof are welded together under controlled factory conditions, often in a climate-controlled workshop to ensure welding quality and surface coatings.
What material and thickness are used for the silo body?
The body is usually made from S355 structural-grade steel plates with a thickness of about 6–12 mm, depending on the silo’s diameter and height.
What corrosion protection methods are applied?
All welded seams are inspected before coating, and both the inside and outside surfaces receive either hot-dip galvanizing or multi-layer epoxy/paint systems. Local reinforcements are also added at weld and bolt areas for better protection.
Structural Features and Stability
Structural stability is ensured by stiffeners and supports built into the welded shell. Many silos use horizontal “girdle” rings or spiral ribs to counter hoop stress; for example, Lipp-style spiral silos have external embossed strips that greatly improve torsion resistance. In all cases, vertical stiffeners are welded on the interior walls and around openings (manholes, chutes) to prevent deformation under full load. The conical base and cylindrical walls are welded integrally, so the silo behaves as one rigid unit. Detailed engineering analyses (to ASME/EN or local codes) ensure the silo can withstand full static pressure, seismic forces and wind loads. As a result, even large silos remain stable under heavy load. For example, monoblock silos up to 120 t capacity (several meters in diameter and height) can often be lifted by air-pressurizing the inside during erection, eliminating the need for a heavy crane for the roof.
MATERIAL FLOW AND DISCHARGE
Material Flow and Cone Design
nside, welded cement silos incorporate several flow-assistance features.
The cone section at the bottom funnels the powder to a discharge point. Common discharge devices include screw conveyors, pneumatic tube unloaders, or gravity feed valves.
Flow-Aid Systems
To prevent bridging or rat-holing of dry cement, silos are often fitted with aeration or fluidization aids.
For instance, rows of low-pressure air pads or nozzles (“fluidization pads”) are installed in the cone base: by bubbling air through the powder, these prevent “rat-holing” and ensure complete discharge.
External vibratory devices may also be attached to the silo walls; forced vibration periodically loosens stuck cement and promotes flow.
Dust Control and Monitoring
The silo’s top usually includes a dust collector (baghouse filter) and filtered vent to allow air inflow without escaping dust.
All silos come with level measurement systems (e.g. radar or weight scales) to monitor remaining inventory. These combined features ensure reliable, steady material delivery to the batching plant with minimal downtime.
Polygonmachine silos, for example, are supplied with pneumatic conveyors, screw feeders, and butterfly valves as optional accessories to tailor the discharge system to each plant’s needs.
Corrosion Protection and Safety
Corrosion protection and safety are critical elements in the design and operation of welded cement silos, as these structures are constantly exposed to harsh environmental conditions, abrasive materials, and potential mechanical stress. Effective corrosion prevention ensures the longevity and structural integrity of the silo, while advanced safety features protect both the equipment and personnel during daily operations. Together, these measures guarantee that the silos can perform reliably for decades, even under demanding industrial conditions such as concrete batching plants and mining facilities.
Corrosion Protection Measures
Cement is abrasive and slightly alkaline, so silo interiors are protected by abrasion-resistant coatings, and exteriors are fully galvanized or painted to withstand weather. Galvanized zinc coatings (with typical thicknesses of ~85–275 g/m²) form the primary barrier against atmospheric corrosion. Design details such as sloped tops and water-diversion gutters prevent water ponding on roofs, while closed weld zones and sealed bolt areas minimize rust hotspots. Periodic maintenance includes re-coating or zinc-spraying of any wear areas and lubrication of moving parts (e.g. valves).
Safety Mechanisms and Features
Safety features are integral. A pressure-relief valve on the top vents protects against overpressure from filling or heat build-up. Manholes have safety bars, and ladders have cages and fall-arrest provisions. Level sensors prevent overfill, and platforms with guardrails allow safe inspection and maintenance.
Industrial Safety Standards
In hazardous environments (e.g. silos handling cement dust near welding), inerting or ignition control measures are applied. Overall, welded silos are engineered to high industrial safety standards, reflecting their use in large concrete and mining operations.
APPLICATIONS AND INSTALLATIONS
Monoblock welded silos are especially common in high-throughput concrete batching plants. In a plant, one or more silos stand next to aggregate bins and mixers, delivering cement to the mixer via conveyor or pneumatic line. Because they are pre-welded, installation can be very fast – a typical 100 t welded silo can be set in a day or two once the foundation is ready. This makes them ideal for turnkey ready-mix plants.
Concrete Plant Applications
For example, Polygonmachine has supplied welded silos (60–120 t class) to North American ready-mix producers upgrading their concrete facilities, as well as to European large-scale projects.
Mining and Heavy Construction
In mining and heavy construction, the same silos (often called “mineral silos” when storing fly ash, slag or grinding aids) serve as on-site cement buffering or bulk material storage. One recent installation saw 80 t welded silos integrated into a U.S. concrete-block production plant, and a pair of custom-designed mineral silos installed at a European limestone quarry for cementitious material storage. These real-world cases highlight the durability and flexibility of Polygonmachine’s welded silo solutions.
Specifications and Performance Features
| Feature | Specification / Detail |
|---|---|
| Capacity | ~30 t to 500 t (up to 1000 t+ for special projects) |
| Shape | Vertical cylinder with conical (hopper) bottom and dome roof |
| Material | High-strength carbon steel (e.g. S355), welded construction |
| Wall Thickness | Typically 6–12 mm (varies by height/diameter) |
| Protective Coating | Hot-dip galvanizing or epoxy/PU paint inside & out |
| Access & Safety | Personnel manhole; ladder with cage; guardrail platform |
| Venting | Filtered roof vent and pressure-relief valve (baghouse on fill) |
| Aeration/Aids | Fluidization pads or nozzles in cone; optional wall vibrators |
| Discharge System | Pneumatic conveying, screw feeder, or butterfly valve |
| Level Monitoring | Radar or weigh-scale silo control (continuous levels) |
| Discharge Capacity | Hundreds of kg/min (depending on conveyor/pneumatic system) |
| Design Standards | ASME, EN 1991 (Eurocode), ACI, or local codes |
| Install Method | Single-piece lift (air pressure lift if spiral roof) |
| Operating Temp. | ~–20°C to +80°C (ambient; insulation optional for extremes) |
| Maintenance Interval | ~10–15 years (coating refresh); routine checks annually |
| Expected Lifespan | 20–30+ years with proper maintenance |